1. Field of the Invention
The present invention relates to a motor assembly. In particular, the present invention relates to a motor assembly for folding/unfolding a screen.
2. Description of the Related Art
FIG. 4 of the drawings illustrates a screen 1′ and a conventional motor assembly for moving the screen 1′ to thereby fold/unfold the screen 1′. The motor assembly comprises an outer tube 1′ and a motor control device 2′ mounted in the outer tube 1′. The motor control device 2′ comprises a DC motor and a controlling circuit board for folding/unfolding the screen 1′. The motor control device 2′ is connected to a plug 4′ and a controller 5′. The plug 4′ includes a transformer and a rectifying circuit mounted therein, thereby reducing the voltage and rectifying current from the AC power source before input into the motor control device 2′. The controller 5′ includes an upward button, a downward button, and a stop button for respectively controlling clockwise rotation, counterclockwise rotation, and stop of the motor.
The plug 4′ has a relatively large volume, as the plug 4′ must accommodate a transformer and a rectifying circuit. Installation of the large-size plug 4′ is inconvenient and the resultant assembly is not good-looking.
A recent design of the motor control device 2′ comprises a photosensor device (not shown) including a light transmitter, a receiver, a disc with a light-transmission area, and a transmission device for turning the disc as well as controlling rotation and positioning of the motor. However, the overall volume of the motor control device 2′ is increased. Thus, the size of the outer tube 1′ must be increased for receiving the elements. Further, the outer tube 1′ significantly protrudes outward from the wall to which the outer tube 1′ is mounted, failing to provide a good appearance.